We explore whether buyer groups, in which firms legally purchase inputs jointly, facilitate collusion in the product market. In a repeated game, abandoning the buyer group altogether or excluding single firms from them constitute more severe credible threats, hence, in theory buyer groups...

Retailers may enjoy stable cartel rents in their output market through the formation of a buyer group in their input market. A buyer group allows retailers to credibly commit to increased input prices, which serve to reduce combined final output to the monopoly level; increased input costs are...